1. Field of the Invention
The present invention generally relates to a display panel, and more particularly, to a display panel capable of reducing noise in an effective manner.
2. Description of Related Art
Rapid development of multimedia technologies mostly benefits from a tremendous progress in semiconductor devices or display apparatuses. Among displays, thin film transistor liquid crystal displays (TFT-LCDs) characterized by high definition, efficient space utilization, low power consumption and no radiation have gradually become mainstream products in the display market.
At this current stage, normal medium or small-sized TFT-LCDs are frequently driven by applying AC mode common voltages, e.g., employing a line inversion display technique. Namely, AC common voltages are applied to common electrodes in the medium or small-sized TFT-LCDs. By contrast, large-sized TFT-LCDs are usually driven by applying DC mode common voltages, e.g., employing a dot inversion display technique. In other words, DC common voltages are applied to common electrodes in the large-sized TFT-LCDs.
FIG. 1A is a schematic top view of a conventional medium or small-sized display panel. FIG. 1B is a time sequence diagram illustrating driving signals of the conventional display panel depicted in FIG. 1A. Referring to FIG. 1A, a display panel 100 has a display area AA and a peripheral circuit area PA disposed around the display area AA. The display panel 100 includes a plurality of pixels 110, a data signal line 120, and a common signal line 130. The data signal line 120 is electrically connected to the pixels 110 and is disposed in an intersection of the peripheral circuit area PA and the display area AA. The common signal line 130 is disposed in the peripheral circuit area PA.
Referring to FIGS. 1A and 1B, when the display panel 100 performs a display function, a DC signal V120 is applied to the data signal line, and an AC signal V130 is applied to the common signal line 130 for the pixels 110 to perform the display function. A voltage value of the DC signal V120 is generally less than a minimum voltage value of the AC signal V130. No other metal layers are disposed between the data signal line 120 and the common signal line 130, and the data signal line 120 and the common signal line 130 are in the same conductive layer. Therefore, a signal of the data signal line 120 and a signal of the common signal line 130 interfere with each other, thereby giving rise to variations in an electric field to a certain degree.
The variations in the electric field generated between the data signal line 120 and the common signal line 130 provide a specific acting force for resonating the two metal conductors. Once a vibration frequency generated between the data signal line 120 and the common signal line 130 falls within a frequency range that can be heard by human ear, the display panel 100 produces the noise that discomforts users. Specifically, as a differential value between the AC signal V130 and the DC signal V120 increases, the resonance and the noise increase as well.